1. Field of the Invention
The disclosures herein generally relate to a pattern formation method, a manufacturing method of a piezoelectric film and a manufacturing method of a piezoelectric element.
2. Description of the Related Art
Some ink jet recording apparatuses or liquid drop discharging head used as image recording apparatuses or image forming apparatus such as printers, facsimile machines or copiers including piezoelectric elements are known. The piezoelectric element, for example, has a structure laminating a piezoelectric film and an upper electrode on a lower electrode.
In order to form a piezoelectric film having a desired pattern, for example, a pattern of a hydrophobic film (for example, an SAM (self-assembled monolayer) film) is formed on the lower electrode (first process). A part on the lower electrode where the pattern of the hydrophobic film is not formed is hydrophilic.
Next, only in the hydrophilic part on the lower electrode (the part where the pattern of the hydrophobic film is not formed) a precursor coated film of a piezoelectric film in an amorphous state (non-crystalline state) is formed, and a heat treatment is performed to form a crystallized film (second process). Here, the pattern of the hydrophobic film used in the first process has a property which is thermally decomposed and eliminated at a predetermined temperature, and since a temperature for crystallizing the precursor coated film in the second process is higher than the predetermined temperature for the thermal decomposition for the hydrophobic film, by the heat treatment in the second process the hydrophobic film is thermally decomposed and eliminated.
Since the precursor film of the piezoelectric film is thin, a crystallized film having a predetermined thickness cannot be formed by a single process. Accordingly, by repeating the first process and the second process for a necessary number the thin crystallized films are laminated, and a thick crystallized film (a piezoelectric film having a desired thickness) is manufactured (See, for example, “Micro-patterning of sol-gel-derived PZT thin film with SAM”, H. Suzuki, T. Mori, T. Fujinami, T. Ota, M. Fuji and M. Takahashi, Ceramics International, 30, 1811-1813 (2004), and Japanese Published Patent Application No. 2013-55174)
However, since the pattern of the hydrophobic film is eliminated in the second process, the pattern of the hydrophobic film is newly formed with each repetition of the first and the second processes, and the manufacturing processes become complicated.